DESCRIPTION: This new application presents plans to study, prospectively, the association between dietary patterns and risk of coronary heart disease (CHD), ischemic stroke, and hemorrhagic stroke in cohort studies of 121,700 women age 30 to 55 years at baseline in 1976 (the Nurses; Health Study; NHS) and 51,529 men aged 40-75 years at baseline in 1986 (the Health Professionals Follow-up Study; HPFS). Food consumption data were collected through semiquantitative food frequency questionnaires at baseline and during follow-up in each of the cohorts. Dietary patterns are derived from the food consumption data using factor analysis, cluster analysis, and dietary indexes (based on prevailing dietary recommendations). In addition, using existing datasets from dietary validation studies in sub-samples of the two cohorts, the investigators propos to evaluate the reproducibility and validity of dietary patterns defined by factor/cluster analysis and dietary indexes. Further, using prospectively collected and stored bloods in the NHS (n-32, 826) during 1989-1990 and the HPFS (n-18, 000) during 1993-1994, we propose to examine whether observed associations between dietary patterns and CHD are explained by (or mediated through) plasma biochemical measurements (including serum lipids, thrombotic factors, antioxidants, fasting insulin, and homocysteine levels) in a nested case-control design; and they propose to assess prospectively the relationship between dietary patterns and these biomarkers in the control samples. The funded NHS and HPFS will provide follow-up and documentation of CHD and stroke in addition to covariate information. Assays of biomarkers in the two cohorts are funded through other grants. Overall, the large size of these cohorts, the prospective design, the high follow-up rates, and the availability of archived blood specimens provide a unique opportunity to study the relationship between overall dietary patterns and cardiovascular disease in an extremely cost-efficient manner. This would be the first study to characterize dietary patterns in large cohorts of men and women and relate dietary patterns to CHD and stroke. Finally, this project will enable evaluation of prevailing dietary recommendations in relation to both biomarkers of risk as well as clinical cardiovascular diseases.